It will be possible to determine relative GH deficiency by comparing the 24 hr. GH profiles of older GH-deficient adults with pituitary disease with age-, sex- and body mass index-matched normal older adults. Using the sensitive chemiluminescence assay, GH will be measurable in all samples, allowing accurate comparisons of spontaneous GH release in these elderly populations. Study completed (GH assay only), paper submitted for publication to Clin Endocrinol. Abstract presented 1996. Using the ultrasensitive GH assay, GH release in both older controls and GH deficient adults was evaluated (samples collected by collaborators in England). GH secretion remains pulsatile in GH deficient patients despite the mass effect of hypothalamic-pituitary pathology, pituitary surgery and radiotherapy.